My daughters and I climbed Hinhan Kaga, or Black Elk Peak, a few years back, when the pine beetles were killing many of the trees. We saw a lot of little holes in the bark of dead and dying trees. Some holes had sap running down, some were dry. Sometimes there was a little bug caught in the sap.
We passed a park ranger coming down the mountain. He said that the sap was the trees’ defense. Normally …